In the rich text editor:
@Igorccx
In a comment:
[Igorccx](https://chowlings.com/user/Igorccx)
For Names and Avatars:
In the rich text editor:
%Igorccx
In a comment:
[![Igorccx's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/Igorccx) [Igorccx](https://chowlings.com/user/Igorccx)